In its broadest aspect the present invention pertains to a new and improved apparatus and method for conveying separate liquids into and out of a container. More specifically, however, the present invention is directed to a new and improved ion exchange apparatus and method involving the flow of liquid treated in an ion exchange resin bed out of a container and involving the flow of regenerant solution into the container.
It is well known to treat water utilizing an ion exchange bed to remove various ions from the water being treated. A suitable ion exchange apparatus for this type of utilization is normally constructed so as to utilize a container holding the ion exchange material which is provided with liquid distribution and collection channels, manifolds or similar structures at the opposite ends of the bed of ion exchange material. During the "service" use of such an apparatus for ion exchange purposes water is introduced into the container at one end of the bed and passes through the bed and then out of the container at the other end of the bed. After a period of such use such a bed is normally regenerated by passing a regenerant solution through the bed.
Although such a regenerant solution may be passed through the bed in the same direction in which water is passed through the bed during "service" use of the apparatus, it is frequently desirable to pass a regenerant solution through the ion exchange bed in a direction which is opposite to the direction of flow during service use. This is referred to as countercurrent flow regeneration. Since the reasons for the use of countercurrent flow regeneration are considered to be well known in the field of treating water by ion exchange, it is not considered necessary to discuss it in this specification.
While unquestionably the same channels, manifolds or the like at each end of the container in an ion exchange apparatus can be utilized to convey both the water treated and to convey the regenerant solution used in regenerating the ion exchange bed, such use of the same distribution-collection channels or manifolds is considered to be disadvantageous. This is because different flow conditions are optimum in connection with treating water so as to remove ions from such water and in connection with the regeneration of ion exchange material. It is considered preferable to pass comparatively large quantities of water through an ion exchange bed during normal service conditions at a comparatively low pressure. As opposed to this during regeneration it is considered preferable to pass smaller quantities of the regenerant solution to the bed at a higher pressure.
It is not considered necessary to discuss the reasons for this in detail in this specification since an understanding of the reasons is not considered necessary to an understanding of the present invention. The use of the same channels or manifold type structures in conveying water under service conditions and in conveying a regenerant solution at different times during the operation of an ion exchange bed is not considered desirable because of the different flow requirements during service use of such a bed and during the regeneration of such a bed. In spite of this because of economic considerations it has been commonplace to use the same channels, manifolds or the like for both of these purposes. Such economic factors also make it undesirable to install separate structures for use with water being treated and for use with a regenerant solution.